/******************************************************************************

*  Copyright (C) 2000 by Robert Hubley.                                      *

*  All rights reserved.                                                      *

*                                                                            *

*  This software is provided ``AS IS'' and any express or implied            *

*  warranties, including, but not limited to, the implied warranties of      *

*  merchantability and fitness for a particular purpose, are disclaimed.     *

*  In no event shall the authors be liable for any direct, indirect,         *

*  incidental, special, exemplary, or consequential damages (including, but  *

*  not limited to, procurement of substitute goods or services; loss of use, *

*  data, or profits; or business interruption) however caused and on any     *

*  theory of liability, whether in contract, strict liability, or tort       *

*  (including negligence or otherwise) arising in any way out of the use of  *

*  this software, even if advised of the possibility of such damage.         *

*                                                                            *

******************************************************************************

	MD5C.C - RSA Data Security, Inc., MD5 message-digest algorithm



	Port to Win32 DLL by Robert Hubley 1/5/2000



	Original Copyright:



	Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All

	rights reserved.



	License to copy and use this software is granted provided that it

	is identified as the "RSA Data Security, Inc. MD5 Message-Digest

	Algorithm" in all material mentioning or referencing this software

	or this function.

		  

	License is also granted to make and use derivative works provided

	that such works are identified as "derived from the RSA Data

	Security, Inc. MD5 Message-Digest Algorithm" in all material

	mentioning or referencing the derived work.

	

	RSA Data Security, Inc. makes no representations concerning either

	the merchantability of this software or the suitability of this

	software for any particular purpose. It is provided "as is"

	without express or implied warranty of any kind.

		  

	These notices must be retained in any copies of any part of this

	documentation and/or software.

 *****************************************************************************/
#include <memory.h>
#include <stdio.h>
#include "md5.h"



// Constants for MD5handle routine.

#define S11 ( 7)

#define S12 (12)

#define S13 (17)

#define S14 (22)

#define S21 ( 5)

#define S22 ( 9)

#define S23 (14)

#define S24 (20)

#define S31 ( 4)

#define S32 (11)

#define S33 (16)

#define S34 (23)

#define S41 ( 6)

#define S42 (10)

#define S43 (15)

#define S44 (21)



// F, G, H and I are basic MD5 functions.

#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))

#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))

#define H(x, y, z) ((x) ^ (y) ^ (z))

#define I(x, y, z) ((y) ^ ((x) | (~z)))



// ROTATE_LEFT rotates x left n bits.

#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))



// FF, GG, HH, and II handleations for rounds 1, 2, 3, and 4. Rotation is separate from addition to prevent recomputation.

#define FF(a, b, c, d, x, s, ac) { \
	(a) += F ((b), (c), (d)) + (x) + (unsigned int)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}

#define GG(a, b, c, d, x, s, ac) { \
	(a) += G ((b), (c), (d)) + (x) + (unsigned int)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}

#define HH(a, b, c, d, x, s, ac) { \
	(a) += H ((b), (c), (d)) + (x) + (unsigned int)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}

#define II(a, b, c, d, x, s, ac) { \
	(a) += I ((b), (c), (d)) + (x) + (unsigned int)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}


/////////////////////////////////////////////////////////////////////////////
ctx_md5::ctx_md5()
{
	initialize();
}


/////////////////////////////////////////////////////////////////////////////

// MD5 block update operation. Continues an MD5 message-digest operation, processing another message block, and updating the context.

void ctx_md5::update(const unsigned char *pdata, unsigned int len)

{

	// Compute number of bytes mod 64

	unsigned int index = (unsigned int)((_count[0] >> 3) & 0x3F);



	// Update number of bits

	if((_count[0] += (len << 3)) < (len << 3)) _count[1] ++;

	_count[1] += (len >> 29);



	unsigned int i = 0, size = 64 - index;



	// handle as many times as possible.

	if(len >= size) 

	{

		memcpy(&_inner_data[index], pdata, size);

		handle(_state, _inner_data);



		for(i = size; i + 63 < len; i += 64)

		{

			handle(_state, &pdata[i]);

		}

		index = 0;

	}

	// _inner_data remaining input

	memcpy(&_inner_data[index], &pdata[i], len - i);

}



// MD5 finalization. Ends an MD5 message-digest operation, writing the the message digest and zeroizing the context.

void ctx_md5::finish(unsigned char cid[16])

{

	/////////////////////////////////////////////////////////////////////////////

	static unsigned char PADDING[64] =

	{

		0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

		   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

		   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

		   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

	};	

	unsigned char val[8];



	// Save number of bits

	encode(val, _count, 8);



	// Pad out to 56 mod 64.

	unsigned int v = (unsigned int)((_count[0] >> 3) & 0x3f);

	unsigned int size = (v < 56) ? (56 - v) : (120 - v);



	update(PADDING, size);



	// Append length (before padding)

	update(val, 8);



	// Store _state in digest

	encode(cid, _state, 16);



	// Zeroize sensitive information.

	initialize();

}





/////////////////////////////////////////////////////////////////////////////

void ctx_md5::initialize(void)

{

	_count[0] = 0;

	_count[1] = 0;

	

	_state[0] = 0x67452301;

	_state[1] = 0xefcdab89;

	_state[2] = 0x98badcfe;

	_state[3] = 0x10325476;



	memset(_inner_data, 0, sizeof(_inner_data));

}



// MD5 basic handleation. handles _state based on block.

void ctx_md5::handle(unsigned int *state, const unsigned char block[64])

{

	unsigned int a = state[0], b = state[1], c = state[2], d = state[3];

	unsigned int x[16];



	decode(x, block, 64);



	/* Round 1 */

	FF(a, b, c, d, x[ 0], S11, 0xd76aa478); /*  1 */

	FF(d, a, b, c, x[ 1], S12, 0xe8c7b756); /*  2 */

	FF(c, d, a, b, x[ 2], S13, 0x242070db); /*  3 */

	FF(b, c, d, a, x[ 3], S14, 0xc1bdceee); /*  4 */

	FF(a, b, c, d, x[ 4], S11, 0xf57c0faf); /*  5 */

	FF(d, a, b, c, x[ 5], S12, 0x4787c62a); /*  6 */

	FF(c, d, a, b, x[ 6], S13, 0xa8304613); /*  7 */

	FF(b, c, d, a, x[ 7], S14, 0xfd469501); /*  8 */

	FF(a, b, c, d, x[ 8], S11, 0x698098d8); /*  9 */

	FF(d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */

	FF(c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */

	FF(b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */

	FF(a, b, c, d, x[12], S11, 0x6b901122); /* 13 */

	FF(d, a, b, c, x[13], S12, 0xfd987193); /* 14 */

	FF(c, d, a, b, x[14], S13, 0xa679438e); /* 15 */

	FF(b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

	

	/* Round 2 */

	GG(a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */

	GG(d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */

	GG(c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */

	GG(b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */

	GG(a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */

	GG(d, a, b, c, x[10], S22, 0x02441453); /* 22 */

	GG(c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */

	GG(b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */

	GG(a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */

	GG(d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */

	GG(c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */

	GG(b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */

	GG(a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */

	GG(d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */

	GG(c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */

	GG(b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

	

	/* Round 3 */

	HH(a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */

	HH(d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */

	HH(c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */

	HH(b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */

	HH(a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */

	HH(d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */

	HH(c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */

	HH(b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */

	HH(a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */

	HH(d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */

	HH(c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */

	HH(b, c, d, a, x[ 6], S34, 0x04881d05); /* 44 */

	HH(a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */

	HH(d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */

	HH(c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */

	HH(b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */

	

	/* Round 4 */

	II(a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */

	II(d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */

	II(c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */

	II(b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */

	II(a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */

	II(d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */

	II(c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */

	II(b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */

	II(a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */

	II(d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */

	II(c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */

	II(b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */

	II(a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */

	II(d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */

	II(c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */

	II(b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */

	

	state[0] += a;

	state[1] += b;

	state[2] += c;

	state[3] += d;



	memset(x, 0, sizeof(x));

}



// Encodes input (unsigned int) into output (unsigned char). Assumes len is a multiple of 4.
void ctx_md5::encode(unsigned char *outdata, const unsigned int *indata, unsigned int len)
{
	for(unsigned int i = 0, j = 0; j < len; i++, j += 4) 

	{

		outdata[j+0] = (unsigned char)((indata[i]) & 0xff);

		outdata[j+1] = (unsigned char)((indata[i] >>  8) & 0xff);

		outdata[j+2] = (unsigned char)((indata[i] >> 16) & 0xff);

		outdata[j+3] = (unsigned char)((indata[i] >> 24) & 0xff);

	}

}



// Decodes input (unsigned char) into output (unsigned int). Assumes len is a multiple of 4.

void ctx_md5::decode(unsigned int *outdata, const unsigned char *indata, unsigned int len)
{
	for(unsigned int i = 0, j = 0; j < len; i++, j += 4)

	{

		outdata[i] = (( unsigned int)indata[j+0]) | (((unsigned int)indata[j+1]) << 8) |

					 (((unsigned int)indata[j+2]) << 16) | (((unsigned int)indata[j+3]) << 24);

	}
}

